Ankle joint for artificial limb



July 27, 1965 c. s. FARNETH 3,196,463

ANKLE JOINT FOR ARTIFICIAL LIMB Filed May 23, 1962 2 Sheets-Sheet 1 Fig.6

63 Ill! 2 36 3 I HM 54 Clayton 5 F arnefh INVEN TOR.

BY w I (am W 3% July 27, 1965 c. s. FARNETH 3,196,463

ANKLE JOINT FOR ARTIFICIAL LIMB Filed May 25, 1962 2 Sheets-Sheet 2 Fig. 2

3 Fig.3

Clayton 5. Fame #1 INVENTOR.

BY WM United States Patent 3,196,463 ANKLE JUINT FUR ARTIFICIAL LIME Qlayton S. arneth, Beaver, Pa. (RD. 2, Box 490-11, New Kensington, Pa.) Fiied May 23, 1962, Ser. No. 196,976 Claims. (Ci. 3--32) This invention relates to flexible coupling devices, and particularly to improved flexible resilient couplings for connecting an artificial foot to an artificial leg.

Accordingly, it is the primary object of the invention to provide an improved coupling between an artificial foot and an artificial leg so that in use it functions in the same manner as a human ankle.

It is another object of the invention to provide a resilient coupling for connecting an artificial foot to an artificial leg so that the coupling normally maintains a natural relative position between the foot and leg and yet permits the foot to move within limits inany direction relative to the leg. Thus, the resilient coupiing functions as a universal joint.

It is another object of the invention to provide a resilient coupling for connecting artificial body members but permits the members to move in any direction relative to one another and tends to return the members to a natural or normal position.

It is another object of the invention to provide an improved flexible coupling that serves as an artificial ankle for connecting an artificial leg and an artificial foot and is provided with improved means for connecting the cou pling to the leg and the foot.

It is a further object of the invention to provide a flexible ankle joint that is provided with adjustable means for selectively regulating the effective stiffness of the joint.

It is still another object of the invention to provide an artificial ankle joint that is so designed that it automatically is protected from contamination by any water or liquid running down the artificial leg to which the joint is connected.

It is yet another object of the invention to provide an artificial ankle joint which is economical to manufacture, durable in use and requires a minimum of maintenance and adjustment.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a perspective view with parts broken away illustrating how the ankle joint connects an artificial leg to an artificial foot;

FIGURE 2 is a vertical cross-sectional view through the ankle joint and portions of the foot and leg shown in FIGURE 1;

FIGURE 3 is a vertical cross-sectional view taken substantially on the plane of line 3-3 in FIGURE 2.

FIGURE 4 is an enlarged vertical cross-sectional view taken substantially on the plane of line 44 in FIG- URE 3;

FIGURE 5 is an enlarged vertical cross-sectional view taken at right angles to FIGURE 4 and substantially on the plane of line 55 in FIGURE 2;

FIGURE 6 is an exploded perspective view of a portion of the ankle joint;

FIGURE 7 is an enlarged perspective view of a portion of the ball socket joint of the ankle joint;

FIGURE 8 is an enlarged perspective view of a detail;

FIGURES 9 and 10 are diagrammatic views illustrating how the ankle joint flexes to permit the foot and leg to move to various relative positions.

As shown in the drawings, the ankle joint or resilient coupling 10 connects the lower end of an artificial leg 12 to the upper portion of an artificial foot 14.

The ankle joint 10 comprises a cylindrical base, body or housing, 16 having a cylindrical reduced upper extension or sleeve-like portion 18 connected to the base 16 by means of an integral, circular and radially outwardly projecting annular flange 20. The base 16 is provided with a chamber 22 defined by a lower circular wall 24 concentric with an upwardly divergent frusto-conical wall 26. The bottom of the chamber 22 may terminate in a conical portion 28.

A connecting rod or joint member 30 provided with a spherical member or ball 32 on its lower end extends into the chamber 22 so that the ball 32 is contained entirely within the cylindrical wall 24. The ball 32 is formed with two frusto-conical coaxial and outwardly divergent recesses 34 extending radially inwardly from opposite sides of the ball so that the apices of the recesses intersect at the center of the ball and define opposing pivot points 36.

A bore 38 is formed diametrically through the center of the base 16 and the cylindrical wall 24. A pair of discs 46 are provided in the bore 38 and each disc has a part spherical recess 42 of the same radius as the ball 32 formed in one end thereof and a bore 4-4 formed through the center thereof.

After the ball 32 has been inserted within the chamber 22, it is rotated so that the centers of the recesses 34 are coaxial with the bore 38. A cylindrical pin 46 is then inserted through one end of bore 38 into the recesses 34 as shown in FIGURE 5. Pin 46 has the same diameter as the maximum spacing between the points 36 and the diameter of the bore 44. The discs 4% are then inserted in opposite ends of the bore 38 so that the recesses 42 thereof engage opposite sides of the ball 32 and the pin 46 extends into the bores or recesses 44. At least the outer ends of the bore 38 is provided with threads so that circular plugs 48 having peripheral threads may be threaded into the outer ends of the bore 38 so as to force the discs 40 tightly against opposite ends of the pin 46 as shown in FIGURE 5. When the plugs 48 are tightly screwed into the bore 38, the recesses 42 of the discs 40 snugly fit the outer periphery of the ball 32 but yet permit the ball to rotate freely in the recesses.

A pair of setscrews 50 are threaded into opposite ends of the base 16 so as to engage the plugs 48 and lock them securely in position. If desired, these studs 50 may extend through apertures in the bottom of the foot 14 so as to secure the base 16 to the foot in addition to locking the plugs 48 in position. Also, if desired, the pin 46 may be shorter than illustrated in FIGURE 5 since the plugs 48 may be locked by the setscrews or studs 50.

As can be seen in FIGURE 7, the upper and lower surfaces of the recesses 34 are semi-circular so that a circular line of contact is maintained between the center of the ball 32 and the pin 46.

The foot 14 is provided with a circular recess 52 for snugly receiving the cylindrical body 16 and flange 20. Diametrically aligned bores are provided in opposite sides of flange 2t) and foot 14 for receiving setscrews or studs 54 which extend through the foot and are threaded into the bores in flange 20 for securing the body 16 to the foot.

The leg 12 contains a hollow chamber 56 in its upper portion and a cylindrical recess 58 in its lower end in alignment with the chamber 56. A bore 69 concentric with the recess 58 connects the reces to the chamber 56.

The central and upper portions of the connecting rod 30 are threaded and a coil spring 62 encircles the central portion of the rod, surrounds the cylindrical extension 18 and rests on the upper surface of flange 20. A nut 63" Having a ci'reula'r flange s4 integral therewith is threaded 'onthe rod30 and extendsnnto 'the spring 62" In operation; the sprin 62 sinceit has and compress the spring between the flanges 64 end-sf parallel" atniireces's'SS between the washer 66 and fl'ange 64. a r

for limited flexibility in each of two vertical planes extending respectively longitudinally and transversely of a foot member, a body with a vertically extending chamber therein, said body being. mounted in and fixedly secured to one of said members, a vertically extending rod having-one end disposed injandsecuredto-the other of said members and having on its other end a ball. secured within and-disposed for journaled movement in said chamber, said" ball having'ia passage .therethrough with a substantially horizontal axis lying in said transverse verticalplane, an ankle. pivot pin carried by said body andfextending transversely thereof and through said V I passage and's'ec'uringsaid' body and the' "associ ated'rnern to one another and pe'rpendicular toitsax is maintains 7 the foot- 14 generally perpendicular-to the leg 12 as'illns trated in FIGURE 2. However, when -the a'nkle joint is usedfor walking on; tilted; surfaces such as 70 in FIGURE 9, the spring will fleX'thifoiig h the angle thereby permitting the bottprn-of thetoot to befully sup orted o'n 'the surface J0. Of course, the angle of sideways tilting of the" foot 14 is limited to substantially her, to said rodg said passage having its mid-portionjournaled on said pin and-halving itsfopposite'erid portions of progressively increasing vertiealextent fr'orii saidfmid portion toward its ends providingclea'rance and limiting the tilting of said body and the associated'meniber about a" substantially horizontal axisEinsaid longitudinal vertical 30 from a n-eutral-pos-ition'by the" contacting of the pin- 46- with the l upper and-lower surfaces'of -the frusto-conical recesses 34in the b'a1l32 and by contact sewer-mast) and wall 26. H u r r When th'e'lartifi cial limb assembly illustrated in the drawings is used for walking, the foot-1 4 is permi-tt'edto" 1 a transverse bore interseeting said'ch'a'rnbet and coaxial; with said passage horizontal axis, a pair ofplugs ea'c'hl rn-ovably received in and being removable through an opposite end of said transverse bore and having a bearing surface engaging said'fb'all; sai'diplug's journ'aling and pivot in the natural manner relative to the leg; 12: as"

illustrated in FIGURE '10 sinee the cir'eu-lar surface or line defined at the centerof the l5all32}by therecesses 34 merely rotates about -the central portionoftheperiph e'ry of the'pin 4 6, Of course, the degreesf of forward and rearward pivoting ofitoot 14 or its leg 12 as illus- V trated in FIGURE; 1'0 may; be limited by the bottom, surfaces 72 of leg 1 2"c'ont'atiting the upper surfaces of foot 14. ore-nurse, the compression'o'f the spring- 62 during the tilting operation also tends to limit the amount of pivot between the leg and the foot However, the

amount of relative pivoting between the leg 12 and foot 14 will normally be limited by the lower portion ofthe rod contacting the fr'us'to-con'i-cal walls 26 otthe base member 16". The spring 62 always ;returnsthe foot to the normal position relative to the leg 1221's illustrated inFIGUR-E 2. The resistance whieh the spring exerts in opposition to any tilting" force maybe regulated" by retaining said ball therebetween and r'e'taining' s'aitl pivot pin in said passage, a closure means removably received 1 beriand deta'chably securing-them together, said body having an upwardly extending sleeve-like portioniii whichadjusting the po'sition of the nut 63- 'on rod'iffl whichirf 7 turn regulates the arnountof compression in the spring; Normally, the maximum angle ,of, pivot permitted between the leg and foot'froin a neutralposition'are illns' trated vin' FIGURES'9' and lU'by the angles A and B. The -Ina'xirnurn' angles and Bare determined by the sides of the lower end of rodeo-abutti g the'surfaces' of? the -fri1 -stoconical wall 26. When the rod contacts: the

wall 26, there is line contact therebtweenj which affords a relatively la'rge'bearin g surface for' limiting movement at the rod; i

The foregoing'iscons'ide'red as illustrative only of the principles" of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not de'siredpto limit the inventionv to the exact construction and opera'tionshown and. de-

scribed, and accordingly, all suitable modifications and of the invention as claimed. 7 7

What is Claimed as new is asefollows: 7 1% An artificial limbincluding artificial leg and foot membersand an ankle joint 'connectin'gsaid members equivalents may be resorted to, falling within the seope plane, said'" chamber "having upwardly diveigent' inner"- surface's' engageable by said rod-and limiting inclination of said body' and its -associated nernb'e'r'jelative' to the vertical axis of saidfrod; said- :Bod'y having thereth'roiigh' each in an; outer end of said' transverse bore and each engaging and 'releasabl'y retaining one of said plugs in" said transverse 'bo're;

2. The eomb-ination of claim 1' including resilient means surrounding said rod and having' portions operatively connected to'isaid" body and to said other member and yieldingly urging them along the axis of saidrod' to a predetermined'relative position.

3; The combination of elaifn' Z'whe'r'ein said bodyhas an extenior'la'terally' projectingmounting flange, fastening means engaging; said" mounting" flange and said' one merriisdisp'osed saiddive'i'gent inner surfaces, said resilient means abutting said mountin'g fiange and embr'aoing said sleeve like'port-ion;

, 4. The combination of claim 1 wherein said plugs have alignedfrecesses" in their adjaee'nt faces "which recesses receive and r aiiithe adjacent ends or s'a'id 'pivot'pin,

5. The combination of olai'rn" 1" wherein said; pa sa e has parallel planar side'walls' whicti said pivot pin is slidably and'guidingly engaged and which sidewalls prevent relative" lateralrnove'ine'nt of said pin in said passage while said vertical clearance between said pin and'passag'e allows but positively" limits'r'ela'tiv'e' vertical movement.

References fiitedby'tlie Examiner 7 UNITED STAT ES PATENTS 42,799-

5/64{ Shepard r3 -32X- 288,239 11/ 3 Ingram 3-32 630,630 '8/99" :Ric'elq 3 32 995,817 -6/11 Vanor'r'nan' ,332 2,726,105, 12 /55 Koenig 287-88 2,877,032 3/59 Fidler' V 2,87 ,90

RICHARD A, ,GAUDET, Primary Examiner 

1. AN ARTIFICIAL LIMB INCLUDING ARTIFICIAL LEG AND FOOT MEMBERS AND AN ANKLE JOINT CONNECTING SAID MEMBERS FOR LIMITED FLEXIBILITY IN EACH OF TWO VERTICAL PLANES EXTENDING RESPECTIVELY LONGITUDINALLY AND TRANSVERSELY OF A FOOT MEMBER, A BODY WITH A VERTICALLY EXTENDING CHAMBER THEREIN, SAID BODY BEING MOUNTED IN AND FIXEDLY SECURED TO ONE OF SAID MEMBERS, A VERTICALLY EXTENDING ROD HAVING ONE END DISPOSED IN AND SECURED TO THE OTHER OF SAID MEMBERS AND HAVING ON ITS OTHER END A BALL SECURED WITHIN AND DISPOSED FOR JOURNALED MOVEMENT IN SAID CHAMBER, SAID BALL HAVING A PASSAGE THERETHROUGH WITH A SUBSTANTIALLY HORIZONTAL AXIS LYING IN SAID TRANSVERSE VERTICAL PLANE, AN ANKLE PIVOT PIN CARRIED BY SAID BODY AND EXTENDING TRANSVERSELY THEREOF AND THROUGH SAID PASSAGE AND SECURING SAID BODY AND THE ASSOCIATED MEMBER TO SAID ROD, SAID PASSAGE HAVING ITS MID-PORTION JOURNALED ON SAID PIN AND HAVING ITS OPPOSITE END PORTIONS OF PROGRESSIVELY INCREASING VERTICAL EXTENT FROM SAID MIDPORTION TOWARD ITS ENDS PROVIDING CLEARANCE AND LIMITING THE TILTING OF SAID BODY AND THE ASSOCIATED MEMBER ABOUT A SUBSTANTIALLY HORIZONTAL AXIS IN SAID LONGITUDINAL VERTICAL PLANE, SAID CHAMBER HAVING UPWARDLY DIVERGENT INNER SURFACES ENGAGEABLE BY SAID ROD AND LIMITING INCLINATION OF SAID BODY AND ITS ASSOCIATED MEMBER RELATIVE TO THE VERTICAL AXIS OF SAID ROD, SAID BODY HAVING THERETHROUGH A TRANSVERSE BORE INTERSECTING SAID CHAMBER AND COAXIAL WITH SAID PASSAGE HORIZONTAL AXIS, A PAIR OF PLUGS EACH MOVABLY RECEIVED IN AND BEING REMOVABLY THROUGH AN OPPOSITE END OF SAID TRANSVERSE BORE AND HAVING A BEARING SURFACE ENGAGING SAID BALL, SAID PLUGS JOURNALING AND RETAINING SAID BALL THEREBETWEEN AND RETAINING SAID PIVOT PIN IN SAID PASSAGE, A CLOSURE MEANS REMOVABLY RECEIVED EACH IN AN OUTER END OF SAID TRANSVERSE BORE AND EACH ENGAGING AND RELEASABLY RETAINING ONE OF SAID PLUGS IN SAID TRANSVERSE BORE. 